This invention relates to double acting type compressors, and more particularly to a swash-plate type compressor which is adapted to attenuate pulsations of the compression medium being discharged from the compressor, thereby being low in noise.
Double acting type compressors are generally used as refrigerant compressors in air conditioning systems for vehicles, and typically they comprise a main body formed by a cylinder block and a pair of cylinder heads secured to opposite ends of the cylinder block. The main body has its opposite ends formed with a pair of suction chambers and a pair of discharge chambers, the chambers of each pair communicating with each other via a suction passageway or a discharge passageway formed in the main body. The main body is also formed therein with a suction port opening in one of the suction chambers as well as a discharge port opening in one of the discharge chambers, the ports being connected to an external circuit associated with the compressor.
The cylinder block has at least one cylinder bore formed therein, in which is slidably received a double headed piston which cooperates with the cylinder bore to define pump working chambers therebetween.
As the piston reciprocatingly moves within the cylinder bore, compression medium is sucked into each of the pump working chambers through the suction port and a corresponding one of the suction chambers, compressed therein and discharged into a corresponding one of the discharge chambers, followed by being supplied to the discharge port via the discharge passageway or directly, and then discharged into the external circuit.
In such type compressor, compression medium is discharged into the discharge chambers alternately from the two pump working chambers, that is, in a discontinuous manner. Therefore, the compression medium being discharged is pulsative. However, the compression medium is discharged into the external circuit without having its pulsations attenuated. Such pulsations of the discharge compression medium cause a considerable level of noise during operation of the compressor.
If a muffler is arranged in the compressor or a snubber chamber is formed in the compressor in order to reduce noise caused by the pulsations of the discharge compression medium, the whole size of the compressor will inevitably be large, providing many inconveniences.